New build doesn't post. No video. Power cycles every 20 seconds or so. Help!

[Mugsy]

Not my first build, but my first ASRock and first Ryzen.

I just finished installing a new MoBo (ASRock B450 Pro4), CPU (Ryzen 2200G) & 1 stick of 8GB 2666 memory (which is in the correct slot according to the manual.)

When I power on, the fans come on (including the cpu fan), but the computer never beeps (tiny piezo speaker plugged into MoBo), the monitor never comes on (using onboard video), no lights on the keyboard (tried two, one USB the other ps/2), and the computer shuts itself off then back on every 20 seconds or so (which implies overheating, but I'd at least get a beep if it were, right?)

If anyone else has installed a Ryzen, one thing I'm wondering about is when I removed the heatsink/fan from the box, I noticed it comes with a square of thermal compound already on the contact surface with no protective tape. I didn't touch the surface and mounted it directly to the cpu (which dropped in effortlessly into the socket and clamped into place.) Is this normal (uncovered thermal compound already on the HSF?) The HSF was mounted properly and tightened till the screws stopped (not over-tightened.)

The motherboard has both the 24pin power & 8pin power connectors plugged in. The 450watt PSU is fine as this new build is replacing an old one in the same case.

I tried clearing the BIOS using a jumper.

I searched the forum and found this same question asked a half dozen times (none of it helpful.) I checked the "No post checklist" on THG. Everything seems to be in order.

I sure hope someone can help! TIA

 

[alexoiu]

If removing the RAM and starting the board, still no beeps?

 

[Mugsy]

If removing the RAM and starting the board, still no beeps?

Thx for the reply.

I'll try reseating the memory though it seems unlikely to be the cause. It's in flat & securely (no wobble), and I should at least get beeps if it were at fault. And why won't the keyboard lights flash?

I also tried clearing the BIOS again this morning.

I'm wondering if there's a possible short on the underside of the motherboard. Only 6 of the 8 standoffs are screwed in. The mounting holes on this ASRock MoBo don't all match up with the case (Zalman Z9 U3). So two mounting holes (both on the lower right) are empty. One stand-off is under the board under a spot where there is no screw-hole but providing support (the other is exposed, not covered by the MoBo.)

I'd really hate to have to pull out the entire MoBo once again just to find out, but I may (eventually) have no choice. If it's a bad MoBo, it'll have to come out anyway. But I'd prefer to rule out both first.

 

[Mugsy]

If removing the RAM and starting the board, still no beeps?

Quick follow-up. Yep. That was it. All I had to do was reseat the memory (a single stick of 8gb ram) and the computer booted!

Hurrah! Thx.

 

[alexoiu]

You're welcome. Glad it helped.